What is the difference between the verbs "anzala" (أَنزَلَ) and "nazala" (نزل), as they are mentioned in the Holy Quran?

Ibn Manzur, in Lisan al-Arab, mentioned that "nazzala" (نَزَّل) and "anzala" (أنزَل) have the same meaning, and that some linguists differentiated between them without stating the reason for the difference. However, Abu al-Hasan (definition) believes that the only difference is the intensification in "nazzala." Al-Zamakhshari, in Al-Kashshaf, opines that "nuzzila" (نُزِّل) in the verse (لَوْلا نُزِّلَ عَلَيْهِ الْقُرْآنُ جُمْلَةً وَاحِدَة - "Why was not the Qur'an sent down to him all at once?") means "anzala." The verb "nazzala," being on the "fa‘‘ala" (فعَّل) pattern, indicates exaggeration or intensification, while "anzala," on the "af‘ala" (أفعل) pattern, does not. To understand their meanings in the Quran, one should refer to books of exegesis such as Tafsir (definition) al-Qurtubi, Ibn Kathir, and Al-Biqa'i.